The structure and function of the cells and tissues of the corneoscleral trabecular meshwork are being examined to learn more of the process of aqueous outflow and control of intraocular pressure. Such knowledge may contribute to full comprehension of various types of glaucoma, and to potential improvements in treatment of glaucoma, or possibly its prevention. In cats and monkeys we are investigating the proliferative and synthetic capabilities of trabecular meshwork cells, following quantitatively by auto radiography and electron microscopy their mitosis and the synthesis and deposition of glycosaminoglycans, collagen, and glycoproteins by these cells. Related histochemical studies on animal eyes and on excised human eyes, both normal and glaucomatous, are being performed to locate glycosaminoglycans. The immediate and long term fate of trabecular endothelial cells after injection of particulate materials into the anterior chamber is being investigated in animals. Trabecular endothelial cells are being established in culture, where their synthetic activity and responses to iris pigment particles, drugs and poisons are being studied.